In the die casting industry, charges of molten metal are in general loaded into a die casting machine by ladling a charge large enough to assure that the molds are completely filled. Accordingly significant waste of metal and excess heating energy is incurred by overloading dies with molten metal charges. Yet the possibility of incompletely filled molds and resulting defective molded parts requires that the die be overloaded for each casting cycle. Thus, it is desirable to improve the state of this art by precisely metering into the die-casting machine just enough molten metal for each charge to assure quality castings.
I have previously introduced machines for metering charges into dies with high accuracy as disclosed in my U.S. Pat. No. 4,428,413, Jan. 31, 1984: HIGH ACCURACY INJECTOR FOR DIE CASTING MACHINES AFFORDING AUTOMATIC METAL LEVEL COMPENSATION. However these machines meter a precise quantity of charge from a molten metal reservoir in a manner not particularly suited for use with the pressure die casting process with horizontal dies actuated by moving die halves into mating registration for molding and separating them for ejection. Typical prior art for such systems is disclosed in U.S. Pat. No. 4,354,545, W. M. Goldhammer, Oct. 19, 1982 for MODIFIED PRESSURE CASTING PROCESS.
It is particularly advantageous in these systems to use the pressure die-casting mode thereby speeding up the cycle time and compacting the charge to remove residual gases. However, prior art horizontal mold systems have inherently required ladling the charge of molten metal, thus introducing waste of metal and energy. Furthermore processing time, cost and inconvenience is encompassed in handling and removing residual overflow "biscuits" inherent in the prior art systems.
Typical of pressure die casting systems is U.S. Pat. No. 2,972,172, A. P. Federman, Feb. 21, 1961 for METHOD FOR FEEDING LIQUID CASTING MATERIAL INTO AN ARTICLE MOLD. This vertical die casting machine, leaves a residual overflow biscuit in the feeding system that must be processed and contributes to metal and energy waste.
There is no known automated pressure die casting system operable with horizontal die casting machines for adjustably metering out precisely measured molten metal charges that avoid waste and yet assure completely filled dies.
It is accordingly an objective of this invention to provide for improved and automated metering of charges in pressure die casting systems for horizontal die casting machines.
Further objects, features and advantages of the invention will be found throughout the following description, drawings and claims.